The question of what happens when the last Bitcoin is mined around 2140 has become a pressing topic as approximately 93.3% of the 21 million supply cap has already been extracted. Currently, Bitcoin miners earn revenue through block subsidies (3.125 BTC per block after the April 2024 halving) and transaction fees. Once the subsidy reaches zero, miners will rely entirely on transaction fees, sparking debate about long-term network security.
Bitcoin's difficulty adjustment algorithm helps sustain security by automatically increasing profitability for remaining miners when others exit. However, critics argue that transaction fees have not risen enough historically to compensate for declining subsidies. Proponents counter that by 2140, Bitcoin adoption and transaction volume will be dramatically higher, creating a robust fee market.
Meanwhile, the ETF landscape is dramatically reshaping Bitcoin's institutional access. The SEC approved spot Bitcoin ETFs in January 2024, and cumulative net inflows have reached roughly $58.4 billion as of late April 2026. BlackRock's IBIT holds approximately $61.9 billion in net assets, while GBTC has seen $26.26 billion in cumulative outflows. Between April 14-24, spot Bitcoin ETFs added about $2 billion in net inflows, though a single-day outflow of $263.2 million on April 27 demonstrated the mechanism's capacity for rapid reversals.
Bloomberg Intelligence data shows stocks with rising passive ownership have returned up to 224.8% over three years, while those losing passive ownership fell 41.4%. This suggests that Bitcoin, now accessible through standard brokerage rails via ETFs, could experience similar concentration effects. A 2025 Fed note found crypto ETP bid-ask spreads comparable to those of other ETFs, and argued that NAV premiums warrant monitoring as a measure of interconnectedness between crypto and equity markets.
The macro environment remains pivotal. April CPI is nowcast at 3.56% and PCE at 3.60%, with the Fed pausing through its June 16-17 meeting. If inflation stays steady and Treasury yields remain anchored near 3.78% (2-year) and 4.31% (10-year), allocation math could drive Bitcoin into an $88,000-$105,000 range. However, a hawkish turn could push BTC to $60,000-$72,000. BlackRock's Spring 2026 outlook characterizes the macro setup as a mild stagflationary trade-off, with the Fed moving toward gradual easing only if inflation cools or growth moderates.
Other proof-of-work cryptocurrencies like Litecoin and Bitcoin Cash have similar supply caps and halving schedules, facing comparable questions about fee-based sustainability. Ethereum eliminated mining entirely by transitioning to proof-of-stake in 2022, using validator staking for network security.
